Ear & CNS

Question 1

Parts of Middle ear

Answer 1

1. Tympanic cavity
2. Auditory ossicles
   Auditory (eustachina/pharyngotympanic) tube

Question 2

Which nerve is in close proximity to the middle ear?

Answer 2

Facial Nerve- CN. 7

Question 3

What is the function of the Eustachian Tube?

Answer 3

It is a canal that connects the middle ear to the nasopharynx, which consists of the upper throat and the back of the nasal cavity. It controls the pressure within the middle ear, making it equal with the air pressure outside the body.

Question 4

What protects the ear from loud sounds?

Answer 4

Stadium m. (muscle of stapes)

Question 5

Explain how sound is transmitted from the external ear to the middle ear

Answer 5

Vibration of sound on the tympanic membrane is transmitted through the middle ear to the cochlea via the ossicles

Question 6

Part of the inner ear that contains perilymph

Answer 6

Bony Labyrinth

Question 7

Part of the inner ear that contains endolymph

Answer 7

Membranous Labyrinth

Question 8

3 auditory ossicles in the middle ear

Answer 8

1. Malleus
2. Incus
3. Stapes

Question 9

Part of the inner ear that contains utricle & saccule

Answer 9

Vestibule

Question 10

What produces endolymph?

Answer 10

Stria vascular

Question 11

Organ for hearing & equilibrium

Answer 11

Inner ear

Question 12

“sound-collecting & conducting apparatus”

Answer 12

external ear & middle ear

Question 13

List the Meninges & their location

Answer 13

1. Dura mater (outermost layer)
2. Arachnoid (attached to dura matter)
3. Pia mater (inner most, adherent to brain & spinal cord. highly vascular)

Question 14

What does white matter in the brain contain?

Answer 14

myelinated axons glial cells, blood vessels

Question 15

What does gray matter contain in the brain?

Answer 15

neurons, glial cells, axons, & blood vessels

Question 16

Oligodendrocytes are glial cells that do what?

Answer 16

provide support & production of myelin sheath to axons within the CNS

Question 17

What are the functions of Microglia ?

Answer 17

function as macrophages (scavengers) in the central nervous system. Immunosurveillance, Immunoregulation, Reparative (phagocytic)

Question 18

Gitter cells

Answer 18

they are microglial cells that are globular & swollen after having phagocytize debris from injured cells. They are weighed down with degenerating myelin.

Question 19

Ectodermal Origin (sensitive to hypoxia, meaning they can’t survive without oxygen)

Answer 19

neurons
astrocytes
oligodendrocytes

Question 20

Mesodermal origin (not as sensitive to hypoxia, so they can survive longer without oxygen)

Answer 20

Microglia

Vascular endothelium

Question 21

Neuroglia/Glial Cells/Glia “Glue”

Answer 21

support cells within the brain & outnumber neurons 50:1

Some of these form myelin

Question 22

List types of neuroglia

Answer 22

1. Astrocytes
2. oligodendrocytes
3. Ependymal cells
4. Microglia

Question 23

Two Types of Astrocytes

Answer 23

Protoplasmic (gray matter)

Fibrillar (white matter)

Question 24

Functions of Astrocytes

Answer 24

1. transport of nutrients
2. part of blood brain barrier
3. antigen presentation
   * very numerous*

Question 25

What forms myelin?

Answer 25

Oligodendrocytes form Myelin in the CENTRAL NERVOUS SYTEM. Schwann cells make it int PERIPHERAL NERVOUS SYSTEM

Question 26

What produces CSF?

Answer 26

choroid plexuses of the lateral, 3 & 4th ventricles of the brain

Question 27

The fetal cerebellum& cerebellum of a new born has an additional _____

Answer 27

exterior cortical lamina

Question 28

Are nerves & ganglia found inside the CNS?

Answer 28

No. They are found OUTSIDE the CNS

Question 29

List the cells present in a nerve

Answer 29

Endothelial cells, fibroblasts, schwann cells

Question 30

List the two types of Ganglia

Answer 30

1. Sensory (craniospinal)

2. Autonomic

Question 31

What is the myenteric plexus?

Answer 31

it is the major nerve supply to the GI tract & controls GI tract motility. It helps control peristaltic movement of the gastrointestinal tract circular. It is situated between the inner & outer longitudinal layers of the tunica muscular